Super rich, impossible to jet help please

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Super rich, impossible to jet help please

Post by ncdogman »

Bought a 2000 KDX200 last November. Got it from a kid that didn't know too much, and by looks, this thing doesn't have that much time on it. It was running super rich at 300-500 foot elevation where I bought it and I thought it would be an easy fix. Got it home to 2500+ foot elevation, now the jetting game begins. Steped it down to a 138 main, from a 160 stock. Went up 3 needles, and even put on top clip, with a 40 pilot, and freeking thing is rich as a Rockafellar. No joke I will dump over a gallon at a time, and ill go to the end of my dirt road and back, 5 times its empty, and that is about 4 miles tops all 5 trips. So I'm getting roughly 4 mpg. So question is WTF? Brand new reeds I put in, good compression, bought new intake side carb boot(freeking$65.00). Took off the side kips cover...good movement according to rpm, not hanging up, it's got me stumped other then carb is toast, never seen that before so its a new to me situation. Freeking carb is soooo clean, oh ya, and I changed the jet block gasket, and tested it with the air blowing through the hose method, no leaks....im stumped.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Super rich, impossible to jet help please

Post by KDXGarage »

Float valve closing?

Fuel level?
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Re: Super rich, impossible to jet help please

Post by ncdogman »

Put a new float needle in, does not come out the overflow tube when its running at idle or off, I can't see it when I'm riding it. Adjusted the float height as best I could. It is not the same as my yz....or something is up with that carb on the kdx. Seems a super fine line between correct and not correct. Thats what I was thinking, that the floats when running arent closing as they should, and its flooding out. If i get it cleared out in top end when riding, it stays cleared out, as soon as i stay off the gas for any amount of time, then re apply throttle...its all loaded up like i just started it. Then bobbles until cleared out...and fine again. Was thinking at full throttle, its using more fuel then being replaced, and thats why it cleans out. Then when you let off the gas, more is being replaced then being used....and load up happens. I dont want to waste the money buying new floats, when that could be towards the new carb. I hate not knowing the history of a bike. I wonder how i can test if its the floats all screwed up
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Re: Super rich, impossible to jet help please

Post by ncdogman »

But what gets me is with a 138 main, and 3 needles bigger, it should be about to blow up, but runs perfectly when cleared out in powerband. I've never seen this before. However bought a used big bear 400, and ran real rough, cleaned carb, ran same. Looked at the pilot, someone drilled holes in it. Changed jets, still ran like crap. Bought a new carb, running like brand new, never had problems since.
User avatar
Molly's 70
Platinum Member
Platinum Member
Posts: 563
Joined: 04:29 pm Jun 18 2017
Country: USA
Location: Wichita, Kansas USA

Re: Super rich, impossible to jet help please

Post by Molly's 70 »

How are the float's? Check float height?
If you lend someone $20, and never see that person again, it was probably worth it.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Super rich, impossible to jet help please

Post by KDXGarage »

If it were mine, I would put the proper sized jets in it, then test from there. It is being altered to cover up some issue. It is now having multiple issues.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Re: Super rich, impossible to jet help please

Post by ncdogman »

I see setting float height is not the norm with the KDX. It is not the same as setting in my YZ...that went simple. This is different. I'm wondering if the float tab was bent all to crap, thats why its giving me problems setting like normal. However I have seen tons of posts that you cant set float height the normal way by looking at carb for reference. I have read the only way to do it proper is by the hose on float bowl method, then holding the line next to carb, and looking at fuel level in hose to the reference point on carb just on these KDX's for some reason.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Super rich, impossible to jet help please

Post by KDXGarage »

Can you put the correct jets in, then bend the tab a little and go ride?
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Re: Super rich, impossible to jet help please

Post by ncdogman »

Done that. I'm wondering if I shouldn't overbend the tab to see how it runs having less fuel in bowl? When you shut the petcock off, and let it run out of gas...it runs better a while before it does the normal high rev right before running out of fuel completely. That tells me when the fuel level gets to a certain point, its not flooding out anymore which would be the float height
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Re: Super rich, impossible to jet help please

Post by ncdogman »

Id hate to spend money on new floats, and its the carb having vacuum issues not drawing fuel properly because its a ebay used carb or something thats worn out
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Re: Super rich, impossible to jet help please

Post by ncdogman »

The float tab is not like on my YZ...the YZ has a nice little dip that the hanger sits in nicely. On the KDX it is super flat. Is that normal?
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Super rich, impossible to jet help please

Post by KDXGarage »

I would "overbend it", but not until the normal jets are in there. The jet sizes are a Band-Aid for something else.

Can you post a picture of what you are looking at? Maybe someone here can see something wrong.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
User avatar
TwistedRoot
Gold Member
Gold Member
Posts: 323
Joined: 02:56 pm Oct 08 2017
Country: United States
Location: Florida, US

Re: Super rich, impossible to jet help please

Post by TwistedRoot »

Sounds similar to my issue with the float valve (?) body needing polishing. I have not leaked fuel since doing that. If I can find the thread I will post it.
2002 KDX 200
2003 KDX 220
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Super rich, impossible to jet help please

Post by KDXGarage »

I would be concerned that if the problem was the float, then you adjusted it to normal and rode it with the wrong jets, it might do damage.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
John_S
Gold Member
Gold Member
Posts: 875
Joined: 06:59 am Jan 27 2017
Country: US
Location: Florida

Re: Super rich, impossible to jet help please

Post by John_S »

You can set the float height on these the manual way. You don’t need the hose filled with fuel method. If you have calipers set them to 18mm, hold the carb upside down at a 45 degrees angle or enough where it’s not compressing the plunger and set it like that. If you don’t have calipers cut or find something 11/16 - 3/4” and use that for reference. A lot of people on here have had overly rich conditions fixed by setting the float to 18mm. That fixed mine right up. Fatten up the main jet and needle before you do this like KDXGARAGE mentioned. The other thing is polishing the float valve. I’ll look for the YouTube video. It works great with a drill and Q tip.
John_S
Gold Member
Gold Member
Posts: 875
Joined: 06:59 am Jan 27 2017
Country: US
Location: Florida

Re: Super rich, impossible to jet help please

Post by John_S »

Here’s the video. This works quick and fixed took care of an issue I was having. It was really rich and pissing out the overflow while I was riding. Yours might be doing the same thing.
This and the 18mm float height and hopefully you’ll be good to go.

John_S
Gold Member
Gold Member
Posts: 875
Joined: 06:59 am Jan 27 2017
Country: US
Location: Florida

Re: Super rich, impossible to jet help please

Post by John_S »

Also take a look down into the jet block from the top of the carb and look at the needle jet. If the hole is oblong, the carb is toast. It’ll be a rich condition that you can’t tune out.

Google “worn needle jet” and click images
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Re: Super rich, impossible to jet help please

Post by ncdogman »

I will do that stuff, and post back. It may take a few days. I'm prepared to buy a new carb. If I have to I'm thinking of doing the 35mm air stryker. My Yz250 has a 38mm air Stryker, and it is so different of a carb. Way more prescision made. I'm thinking the 35mm air stryker would be an awesome upgrade for the KDX. Ya I know of the modded carbs, but I'm a fan of stock, and going to the air stryker to me is not modding it, its updating it.
ncdogman
Member
Posts: 16
Joined: 03:00 pm Mar 24 2019
Country: United States

Re: Super rich, impossible to jet help please

Post by ncdogman »

O.k. Took carb off, and over set the float to see extreme lean float height. NO CHANGE! The brass insert that the needle goes in does not look wallowed out. This carb has to be shot. There has to be something missing, or carb is just toast. I mean, there could be abosolutely nothing else that would be causing this. My driveway is really steep, and when had it cleaned out up top of property....hitting powerband...ran fine, but as soon as i go down the driveway in 3rd gear not giving any gas till I hit the bottom, it's all loaded up by the time i get down botton(20 sec). Then i go up, and within 100 feet, its cleaned out again, and screaming....let off the gas.....it loads slam up....2 stroke smoke freeking like im fogging mosquitoes. I give up....I'm saving for a new carb.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Super rich, impossible to jet help please

Post by KDXGarage »

MAN! Sorry for the trouble.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
Post Reply